Calcium lactate is a white crystalline

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quant ...

with formula , consisting of two lactate

anion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...

s (CHOH) for each

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...

cation . It forms several hydrates, the most common being the pentahydrate ·5. Calcium lactate is used in medicine, mainly to treat calcium deficiencies; and as a food additive with E number of E327. Some

cheese crystals Cheese crystals are whitish, semi-solid to solid, slightly crunchy to gritty crystalline spots, granules, and aggregates that can form on the surface and inside of cheese. Cheese crystals are characteristic of many long-aged hard cheeses. Hard ...

consist of calcium lactate.

Properties

The lactate ion is

chiral Chirality is a property of asymmetry important in several branches of science. The word ''chirality'' is derived from the Greek (''kheir''), "hand", a familiar chiral object. An object or a system is ''chiral'' if it is distinguishable from i ...

, with two enantiomers, D (−,''R'') and L (+,''S''). The L isomer is the one normally synthesized and metabolized by living organisms, but some bacteria can produce the D form or convert the L to D. Thus calcium lactate also has D and L isomers, where all anions are of the same type. Some synthesis processes yield a mixture of the two in equal parts, resulting in the DL (

racemic In chemistry, a racemic mixture, or racemate (), is one that has equal amounts of left- and right-handed enantiomers of a chiral molecule or salt. Racemic mixtures are rare in nature, but many compounds are produced industrially as racemates. ...

) salt. Both the L and the DL forms occur as crystals on the surface of aging Cheddar cheese.G.F. Tansman, P.S. Kindstedt, J.M. Hughes (2014): "Powder X-ray diffraction can differentiate between enantiomeric variants of calcium lactate pentahydrate crystal in cheese". ''Journal of Dairy Science'', volume 97, issue 12, pages 7354–7362. The solubility of calcium L-lactate in water increases significantly in presence of d-

gluconate Gluconic acid is an organic compound with molecular formula C6H12O7 and condensed structural formula HOCH2(CHOH)4COOH. It is one of the 16 stereoisomers of 2,3,4,5,6-pentahydroxyhexanoic acid. In aqueous solution at neutral pH, gluconic acid f ...

ions, from 6.7 g/ dl) at 25 °C to 9.74 g/dl or more.Martina Vavrusova, Merete Bøgelund Munk, and Leif H. Skibsted (2013): "Aqueous Solubility of Calcium l-Lactate, Calcium d-Gluconate, and Calcium d-Lactobionate: Importance of Complex Formation for Solubility Increase by Hydroxycarboxylate Mixtures". ''Journal of Agriculture and Food Chemistry'', volume 61 issue 34, pages 8207–8214. Paradoxically, while the solubility of calcium L-lactate increases with temperature from 10 °C (4.8 g/dl) to 30 °C (8.5 g/dl), the concentration of free ions decreases by almost one half. This is explained as the lactate and calcium ions becoming less hydrated and forming a complex .Martina Vavrusova, Ran Liang, and Leif H. Skibsted (2014): "Thermodynamics of Dissolution of Calcium Hydroxycarboxylates in Water". ''Journal of Agriculture and Food Chemistry'', volume 62, issue 24, pages 5675–5681. The DL (racemic) form of the salt is much less soluble in water than the pure L or D isomers, so that a solution that contains as little as 25% of the D form will deposit racemic DL-lactate crystals instead of L-lactate.Gil Fils Tansman (2014): ''Exploring the nature of crystals in cheese through X-ray diffraction'' Masters Dissertation, University of Vermont The pentahydrate loses water in a dry atmosphere between 35 and 135 °C, being reduced to the anhydrous form and losing its crystalline character. The process is reversed at 25 °C and 75%

relative humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present. Humidity dep ...

.Yukoh Sakata, Sumihiro Shiraishi, Makoto Otsuka (2005): "Characterization of dehydration and hydration behavior of calcium lactate pentahydrate and its anhydrate". ''Colloids and Surfaces B: Biointerfaces'', volume 46, issue 3, pages 135–141.

Preparation

Calcium lactate can be prepared by the reaction of

lactic acid Lactic acid is an organic acid. It has a molecular formula . It is white in the solid state and it is miscible with water. When in the dissolved state, it forms a colorless solution. Production includes both artificial synthesis as well as nat ...

with calcium carbonate or calcium hydroxide. Since the 19th century, the salt has been obtained industrially by fermentation of

carbohydrate In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or m ...

s in the presence of calcium mineral sources such as calcium carbonate or calcium hydroxide.Kook Hwa Choi, Yong Keun Chang, and Jin-Hyun Kim (2011) "Optimization of Precipitation Process for the Recovery of Lactic Acid". ''KSBB Journal'', volume 26, pages 13-18.
Abstract
Fermentation may produce either D or L lactate, or a racemic mixture of both, depending on the type of organism used.

Uses

Medicine

Calcium lactate has several uses in human and

veterinary medicine Veterinary medicine is the branch of medicine that deals with the prevention, management, diagnosis, and treatment of disease, disorder, and injury in animals. Along with this, it deals with animal rearing, husbandry, breeding, research on nutri ...

. Calcium lactate is used in medicine as an

antacid An antacid is a substance which neutralizes stomach acidity and is used to relieve heartburn, indigestion or an upset stomach. Some antacids have been used in the treatment of constipation and diarrhea. Marketed antacids contain salts of alu ...

. It is also used to treat hypocalcaemia (calcium deficiencies). It can be absorbed at various pHs, thus it does not need to be taken with food. However, in this use it has been found to be less convenient than calcium citrate.Deborah A. Straub (2007): "Calcium Supplementation in Clinical Practice: A Review of Forms, Doses, and Indications". ''Nutrition in Clinical Practice'', volume 22, issue 3, pages 286–296. In the early 20th century, oral administration of calcium lactate dissolved in water (but not in milk or tablets) was found to be effective in prevention of tetany in humans and dogs with

parathyroid Parathyroid glands are small endocrine glands in the neck of humans and other tetrapods. Humans usually have four parathyroid glands, located on the back of the thyroid gland in variable locations. The parathyroid gland produces and secretes pa ...

insufficiency or who underwent parathyroidectomy.Sloan J. Wilson (1938): "Postoperative Parathyroid Insufficiency and Calcium Lactate". ''Archives of Surgery'', volume 37, issue 3, pages 490-497. A.B. Luckhardt and B. Goldberg (1923): "Preservation of the Life of Completely Parathyroidectomized Dogs by Means of the Oral Administration of Calcium Lactate." ''Journal of the American Medical Association'', volume 80, issue 2, pages 79-80. The compound is also found in some mouth washes and toothpaste as an anti-tartar agent. Calcium lactate (or other calcium salts) is an antidote for soluble fluoride ingestionCarolyn A. Tylenda (2011): "Toxicological Profile for Fluorides, Hydrogen Fluoride, and Fluorine (Update)". DIANE Publishing. and hydrofluoric acid.

Food industry

The compound is a food additive classified by the United States FDA as Generally Recognized as Safe (GRAS), for uses as a firming agent, a

flavor enhancer A flavoring (or flavouring), also known as flavor (or flavour) or flavorant, is a food additive used to improve the taste or smell of food. It changes the perceptual impression of food as determined primarily by the chemoreceptors of the gust ...

flavoring agent A flavoring (or flavouring), also known as flavor (or flavour) or flavorant, is a food additive used to improve the taste or smell of food. It changes the perceptual impression of food as determined primarily by the chemoreceptors of the gust ...

, a

leavening agent In cooking, a leavening agent () or raising agent, also called a leaven () or leavener, is any one of a number of substances used in doughs and batters that cause a foaming action (gas bubbles) that lightens and softens the mixture. An altern ...

, a

nutritional supplement A dietary supplement is a manufactured product intended to supplement one's diet by taking a pill, capsule, tablet, powder, or liquid. A supplement can provide nutrients either extracted from food sources or that are synthetic in order ...

, and a stabilizer and

thickener A thickening agent or thickener is a substance which can increase the viscosity of a liquid without substantially changing its other properties. Edible thickeners are commonly used to thicken sauces, soups, and puddings without altering their t ...

.U. S. Food and Drug Administration (2016): ''Code of Federal Regulations: Title 21'' Volume 3, sectio
21CFR184.1207 "Calcium lactate"
revised April 1, 2016 Calcium lactate is also known as cheese lactate because it coagulates milk, making the chhena used in the production of

paneer Paneer (), also known as ponir () is a fresh acid-set cheese common in the Indian subcontinent (Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan and Sri Lanka) made from full-fat buffalo milk or cow milk. It is a non-aged, non-melting sof ...

cheese. Chhena is also used to make various sweets and other milk proteins. Calcium lactate is an ingredient in some

baking powder Baking powder is a dry chemical leavening agent, a mixture of a carbonate or bicarbonate and a weak acid. The base and acid are prevented from reacting prematurely by the inclusion of a buffer such as cornstarch. Baking powder is used to increas ...

s containing

sodium acid pyrophosphate Disodium pyrophosphate or sodium acid pyrophosphate (SAPP) is an inorganic compound consisting of sodium cations and pyrophosphate anion. It is a white, water-soluble solid that serves as a buffering and chelating agent, with many applications ...

. It provides calcium in order to delay leavening.E.J. Pyler (1988), Baking Science and Technology, Sosland Publishing Calcium lactate is added to sugar-free foods to prevent

tooth decay Tooth decay, also known as cavities or caries, is the breakdown of teeth due to acids produced by bacteria. The cavities may be a number of different colors from yellow to black. Symptoms may include pain and difficulty with eating. Complicatio ...

. When added to

chewing gum Chewing gum is a soft, cohesive substance designed to be chewed without being swallowed. Modern chewing gum is composed of gum base, sweeteners, softeners/ plasticizers, flavors, colors, and, typically, a hard or powdered polyol coating. Its t ...

containing

xylitol Xylitol is a chemical compound with the formula , or HO(CH2)(CHOH)3(CH2)OH; specifically, one particular stereoisomer with that structural formula. It is a colorless or white crystalline solid that is freely soluble in water. It can be classifi ...

, it increases the

remineralization In biogeochemistry, remineralisation (or remineralization) refers to the breakdown or transformation of organic matter (those molecules derived from a biological source) into its simplest inorganic forms. These transformations form a crucial link ...

tooth enamel Tooth enamel is one of the four major tissues that make up the tooth in humans and many other animals, including some species of fish. It makes up the normally visible part of the tooth, covering the crown. The other major tissues are dentin, ...

. The compound is also added to fresh-cut fruits, such as

cantaloupe The cantaloupe, rockmelon (Australia and New Zealand, although cantaloupe is used in some states of Australia), sweet melon, or spanspek (Southern Africa) is a melon that is a variety of the muskmelon species (''Cucumis melo'') from the fami ...

s, to keep them firm and extend their shelf life, without the bitter taste caused by

calcium chloride Calcium chloride is an inorganic compound, a salt with the chemical formula . It is a white crystalline solid at room temperature, and it is highly soluble in water. It can be created by neutralising hydrochloric acid with calcium hydroxide. Ca ...

, which can also be used for this purpose. Calcium lactate is used in

molecular gastronomy Molecular gastronomy is the scientific approach of nutrition from primarily the perspective of chemistry. The composition ( molecular structure), properties (mass, viscosity, etc) and transformations (chemical reactions, reactant products) o ...

as a flavorless

fat In nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such compounds, most commonly those that occur in living beings or in food. The term often refers specifically to triglycerides (triple est ...

-soluble agent for plain and reverse spherification. It reacts with

sodium alginate Alginic acid, also called algin, is a naturally occurring, edible polysaccharide found in brown algae. It is hydrophilic and forms a viscous gum when hydrated. With metals such as sodium and calcium, its salts are known as alginates. Its colou ...

to form a skin around the food item.

Animal feeds

Calcium lactate may be added to animal rations as a source of calcium.B.N. Paul, S. Sarkar, S. S. Giri, S. N Mohanty, P. K. Mukhopadhyay (2006): "Dietary calcium and phosphorus requirements of rohu ''Labeo rohita'' fry". ''Animal Nutrition and Feed Technology'', volume 6, issue 2, pages 257-263

Chemistry

The compound was formerly an intermediate in the preparation of lactic acid for food and medical uses. The impure acid from various sources was converted to calcium lactate, purified by crystallization, and then converted back to acid by treatment with sulfuric acid, which precipitated the calcium as

calcium sulfate Calcium sulfate (or calcium sulphate) is the inorganic compound with the formula CaSO4 and related hydrates. In the form of γ-anhydrite (the anhydrous form), it is used as a desiccant. One particular hydrate is better known as plaster of Paris ...

. This method yielded a purer product than would be obtained by distillation of the original acid.H. Benninga (1990): "A History of Lactic Acid Making: A Chapter in the History of Biotechnology". Volume 11 of ''Chemists and Chemistry''. Springer, Recently ammonium lactate has been used as an alternative to calcium in this process."A gypsum-free, energy-saving route to lactic acid" ''Chemical Engineering'', July 1, 2009.

Water treatment

Calcium lactate has been considered as a coagulant for removing suspended solids from water, as a renewable, non-toxic, and biodegradable alternative to

aluminum chloride Aluminium chloride, also known as aluminium trichloride, is an inorganic compound with the formula . It forms hexahydrate with the formula , containing six water molecules of hydration. Both are colourless crystals, but samples are often contam ...

.R. Devesa-Rey, G. Bustos, J. M. Cruz, A. B. Moldes (2012): "Evaluation of Non-Conventional Coagulants to Remove Turbidity from Water". ''Water, Air, & Soil Pollution'', volume 223, issue 2, pages 591–598.

Bioconcrete

Addition of calcium lactate substantially increases the compressive strength and reduces water permeability of bioconcrete, by enabling bacteria such as ''

Enterococcus faecalis ''Enterococcus faecalis'' – formerly classified as part of the group D ''Streptococcus'' system – is a Gram-positive, commensal bacterium inhabiting the gastrointestinal tracts of humans. Like other species in the genus ''Enterococcus'', ''E ...

'', '' Bacillus cohnii'', '' Bacillus pseudofirmus'' and ''

Sporosarcina pasteurii ''Sporosarcina pasteurii'' formerly known as ''Bacillus pasteurii'' from older taxonomies, is a gram positive bacterium with the ability to precipitate calcite and solidify sand given a calcium source and urea; through the process of microbiol ...

'' to produce more calcite.J.M. Irwan, L.H. Anneza, N. Othman, A. Faisal Alshalif (2016): "Compressive Strength and Water Penetration of Concrete with Enterococcus faecalis and Calcium Lactate". ''Key Engineering Materials'', volume 705, pages 345-349. Renee Mors and Henk Jonkers (2017): "Effect on Concrete Surface Water Absorption upon Addition of Lactate Derived Agent". ''Coatings'', volume 7, issue 4, page 51

References

{{Mineral supplements Calcium compounds Lactates Food antioxidants E-number additives